First, whisk the all purpose flour and milk together in a small saucepan until completely smooth. Cook the mixture over medium low heat, stirring constantly, until it thickens into a smooth and glossy pudding like consistency. Once thickened, transfer the tangzhong to a bowl and allow it to cool completely before adding it to the dough.
Next, add the lukewarm milk, granulated sugar and active dry yeast to a large mixing bowl. Stir gently and let the mixture stand for 5 to 10 minutes, or until the yeast becomes slightly foamy. This helps make sure the yeast is active before you continue with the dough.
Add the egg and completely cooled tangzhong to the yeast mixture and mix until combined. Then add the flour, salt and ground cardamom. Mix until a soft dough forms.Begin kneading the dough until it starts to become smooth. Gradually add the softened butter and continue kneading until the dough becomes smooth, silky and elastic. The dough should pass the windowpane test and remain soft and slightly tacky. Avoid adding too much extra flour, as a stiff dough can result in heavier Swedish cinnamon buns. Place the finished dough into a lightly greased bowl and cover it. Leave it in a warm place for approximately 60 to 90 minutes, or until it has doubled in size. Keep in mind that the exact rising time can vary depending on the temperature of your kitchen, so look for the dough to double rather than relying only on the clock.
Meanwhile, prepare the filling by combining the very soft butter, brown sugar, ground cinnamon, vanilla sugar or vanilla extract and a pinch of salt. Mix until you have a smooth and easily spreadable paste. The filling should be soft enough to spread evenly across the dough without tearing it.
Once the dough has doubled in size, transfer it to a lightly floured work surface. Roll it into a large rectangle measuring approximately 30 × 45 cm. Try to keep the thickness as even as possible so that the cinnamon filling is distributed evenly throughout the buns.
Spread the cinnamon filling evenly over the entire surface of the dough. Then fold the dough in half lengthwise, bringing the unfilled edge over the filled side. You should now have a long, layered rectangle with the cinnamon filling enclosed between the layers.
Using a sharp knife or pastry cutter, cut the dough into wide strips. Take one strip and make a lengthwise slit down the center, leaving the top portion attached. You should now have two connected strands.Next, gently twist the two strands around each other, allowing the cinnamon layers to remain visible. Then wrap the twisted strip around itself to create a bun and tuck the loose end underneath to secure it. Avoid twisting the dough too tightly, because the layers need room to expand during the second rise and baking.Place each shaped bun onto a parchment lined baking tray, leaving enough space between them. Cover the shaped buns loosely and let them proof for approximately 30 to 45 minutes, or until they look noticeably puffy and airy. Be careful not to overproof them. Properly proofed Kanelbullar should look light and soft while still holding their beautiful twisted shape.
While the buns finish proofing, whisk together the egg yolk, milk and granulated sugar until smooth. Once the buns are ready, gently brush each one with a thin layer of the egg wash. Then generously sprinkle pearl sugar over the tops for that classic Swedish cinnamon bun finish.
Meanwhile, preheat the oven to 200°C / 390°F conventional or 180°C / 350°F fan. Bake the buns for approximately 10 to 14 minutes, or until they are beautifully golden brown. Keep a close eye on them during the final few minutes so they do not become overly dark. The finished buns should be golden on the outside while remaining soft and fluffy inside.
Finally, transfer the freshly baked buns to a wire rack and allow them to cool slightly. These Soft Swedish Cinnamon Buns are especially delicious while still warm, when the cinnamon filling is fragrant and the crumb is soft and pillowy. Serve them with coffee or tea for a cozy Swedish fika.
